Various safety covers have been devised for covering plug blade-receiving socket openings of extension cord end connectors. These safety covers have taken the form of slide plates mounted on the end connectors, or removable covers with plug elements adapted to fit into one or both of the openings of each set of socket openings. The slide type of covers normally remain connected to the end connector and present a set of openings which register with a respective set of socket openings in the associated end connector when the connector is in an inactive position, ready to receive therethrough the blades of a plug. Then, to cover the mouth of the socket openings when the plug is removed, the cover must be manually shifted if it is to then cover the socket mouths so that a child, for example, cannot insert a foreign object in the end connector. In the case of covers of the type having plug elements, the cover is commonly mounted on the cord adjacent the end connector and is manually manipulated to insert or remove the plug elements.
In the case of either the slide type or plug-in type of safety covers, the cover must be manipulated to return the cover to safety position after the related end connector socket openings have been used. This, of course, means that the person removing the plug from the connector must remember to return the cover to a covering position in order for the cover to carry out its safety function.